Humphry Osmond was a British psychiatrist and psychedelic researcher who coined the word "psychedelic" in a letter to Aldous Huxley in 1956.

In 1952, Osmond began working with psychedelics (particularly mescaline & LSD) while looking for a cure for schizophrenia at Weyburn Mental Hospital in Saskatchewan, Canada. During this time, he suggested that mescaline allowed a normal person to see through the eyes of a schizophrenic and suggested that it be used to train doctors and nurses to better understand their patients. His research attracted the attention of Aldous Huxley, who volunteered to be a subject. In May 1953, Osmond introduced Huxley to mescaline for the first time, an experience described in Huxley's Doors of Perception.

Osmond was part of a community of therapists who worked with mescaline and LSD from the mid-1950s to the mid-1960s. He and Al Hubbard developed a method of using LSD to cure alcoholics of their addiction by attempting to mimic the experience of the extreme low of delium tremens. Later, Osmond and Hubbard realized that psychedelics could be used as a psychotherapeutic tool without attempting to mimic psychotic states.

Osmond served on the board of The Commission for the Study of Creative Imagination, founded by Al Hubbard, along with Abram Hoffer, Sidney Cohen, Aldous Huxley, Gerald Heard, and others.